Exhaust treatment devices in trucks require maintenance procedures that can create situations where exhaust temperatures are much higher than during normal use of the vehicle. For example, diesel particulate filters, which trap soot and other particulate matter in the exhaust stream, require a regeneration process to burn off the collected matter. The process requires that the temperature of the exhaust entering the diesel particulate filter be in excess of 600° C. Normal operating exhaust temperature is about 425° C. for a diesel engine in a truck.
Exhausting the higher temperature stream to atmosphere poses difficulties. A truck typically has an exhaust stack pipe rising from the chassis adjacent to the truck cab. High temperature exhaust can produce a hot spot on the truck cab or trailer, or direct hot gases to a building (such as at a loading dock) or an overhanging tree.
What is needed is a device to reduce the exhaust temperature of an engine during regeneration procedure. Preferably, the device would not drastically affect the exhaust backpressure.